The present invention relates to an aliphatic or alicyclic ketimine and to its corresponding polyamine which are usable in coatings, composites, or adhesives.
Polyamines has found widescale application in the preparation of composites, such as nylons and other polyamides or heterocycles such as imides, oxazoles, or thiazoles. The usefulness of the polyamines. however, is sometimes impacted by their reactivity. To slow and to control their reaction, we have discoverd that the amine functionalities can be blocked with ketones to form novel ketimines. The ketimines might be used as latent moisture cure resins in epoxy coatings or in two-part polyurethane systems where the ketimine evolves to the polyamine and reacts with an isocyanate or reacts directly with the isocyanate, as described in Dr. D. Wicks et al., xe2x80x9cThe Direct Reaction Between Ketimines and Aliphatic Isocyanates,xe2x80x9d Water-Borne and Higher-Solids and Powder Coatings Symposium, Feb. 24-26, 1993, which we incorporate by reference.
The ketimine of the present invention is one component of a novel class of tetraketimines or polyamines useful as latent moisture cure resins or components in composites. The preferred tetraketimine is typically aliphatic and of reasonably high molecular weight to provide toughness with relatively high crosslinking but without brittleness. The tetraketimine is generally made by condensing a diisocyanate with a triamine having two, blocked primary amines and one free secondary amine. A preferred tetraketimine has the formula: 
wherein Et is ethyl, Me is methyl, and R is a residue of a diisocyanate, and, preferably, an aliphatic or alicyclic hydrocarbon.